Solar battery mounting structure in a vehicle

A solar battery mounting structure including a solar battery module (1) in which a frame (B) includes a light transmissive plate member (2), an adhesive portion (S) by which a lower surface of a side end portion of the light transmissive plate member (2) is adhered to an adhesive surface of a vehicle body frame member (B), and a fixation portion which is fixed to a lower surface of the light transmissive plate member through a sealing material layer (4), and is fixed to a fixation surface (F) of the vehicle body frame member facing the lower surface, a protrusion portion in contact with the lower surface of the light transmissive plate member through the sealing material layer is formed in the fixation portion, and frame a step portion is formed between the adhesive surface and the fixation surface.